The outrage over the Palace Museum, also known as the Forbidden City, allowing an SUV to park on its premises despite a years-long ban continues to grow in China, prompting an apology from the curator of the 600-year-old site.

Curator Wang Xudong early on Tuesday released an apology days after photos of two women posing next to a car inside the complex triggered widespread indignation and condemnation. Vehicles have been barred from entering the grounds of the UNESCO World Heritage Site since 2013.

Wang explained that the driver was among over 200 people attending a private event last Monday, when the venue is usually closed to the public.

The curator said the vehicle was parked at a temporary parking lot after the main car park cleared for the event near the West Prosperity Gate reached maximum capacity. The new location was on the southern side of the River of Golden Waters inside the Meridian Gate, which the curator said had been previously used as a parking space. Wang explained that the ground in that area has been modernized and upgraded over the past years.

Read more: Photos of parking inside Forbidden City arouse indignation and questions online

Two high-level managers have been suspended from their duties, Wang said. The deputy director in charge of the Palace Museum, who was responsible for the reception plan, and the director of the security department are currently being investigated over the incident.

The statement noted that relevant departments of the Palace Museum will inspect all vehicle corridors and parking spaces to ensure that no damage is done to the cultural relics.

The now-deleted photos were posted on China's Twitter-like Weibo platform on January 13 and showed two women standing in front of a luxury vehicle parking inside the Palace Museum. Netizens questioned how a car managed to make its way inside despite the ban, and wondered whether this could endanger preservation efforts of the site.

It is not clear whether Wang's post would assuage mounting anger. This is not the first time the Palace Museum has apologized in the wake of the incident. On January 17, the administration expressed its deep sorrow over what had happened, but that was not enough to put an end to the fury.